During hydrocarbon drilling and recovery operations, fluid is often extracted from a drilled wellbore to identify gases present in the fluid in order to analyze formation and/or reservoir characteristics. The fluid is generally removed and sent to a surface location for analysis. However, such surface analysis may delay evaluation of a reservoir prospect by requiring that the fluid samples be removed and sent to a surface lab for analysis, which could take months. Downhole analysis units allow for real time fluid analysis and reduce this delay.
Introducing representative samples into a downhole analysis system is important in providing accurate compositional analysis data. If the inlet system selectively passes some constituents over others, then any measurement of the relative distribution of constituents will be in error unless this selectivity can be quantified and a correction made for it. Therefore, an inlet system that transmits the same distribution of constituents as were originally present is preferred. In a downhole system, introducing representative samples can be very difficult, thus making accurate real-time downhole fluid analysis difficult to accomplish due to the generally inhospitable conditions and space and design restrictions inherent in a downhole environment.